Why is Mercury called Mercury?

When it comes to "five obsidians", it is necessary to talk about "five latitudes". "Five latitudes" is also called "five stars", that is, water, gold, fire, wood and earth in the solar system (arranged in the order from near to far from the sun here, the same below). The name of China's "five stars" first appeared around four or five hundred BC. These five planets were called "Chen Xing", "Taibai", "Huo Ying", "Old Star" and "Zhenxing" in ancient times, and later they gradually became the most commonly used names of these planets. Here are the origins of the corresponding names:

Mercury, called "Chen Xing" in ancient times. It is the closest planet to the sun in the solar system. When observing "Mercury" from the earth, it usually appears on both sides of the sun, and the distance from the sun is always kept within 30 degrees. The "degree" here is an ancient unit in China, and about 30 degrees is a "time". There is a saying of "Twelve Chens" in the 21st Century of New Tang Dynasty, so Mercury was named "Chen Xing" according to the moving distance. "Mercury" is difficult to observe with naked eyes, because "Mercury" has the smallest orbital radius. It is an inner planet and usually crosses the sky with the sun. The strong light of the sun eclipses "Mercury", and only a few days in a year can we successfully observe "Mercury" with the naked eye.

"Water Obsidian", also known as "Chen Xing", is one of the five obsidians of the ecliptic, which had cool water and air in the Ming Dynasty.

In foreign countries, "Seven Obsidian" is also quite famous. In many areas, "seven obsidians" represent seven days of the week. Luna is in charge of Monday, so Monday is called "Moon Obsidian Day"; Vulcan is in charge of Tuesday, which is called "Fire Obsidian Day"; The water god is in charge of Wednesday, which is called "Water Obsidian Day"; Shen Mu is in charge of Thursday, which is called "Obsidian Day"; The golden god is in charge of Friday, which is called "Golden Yao Day"; The land god is in charge of Saturday, which is called "Earth Obsidian Day"; The sun god is in charge of Sunday, which is called "Sun Yao Day". The name "seven outdated days" representing seven days a week first appeared in the ancient Babylonian civilization in the two river basins. Around 700 BC, the system of dividing the week into seven days appeared in Babylon, and the surrounding areas were merged into one month. Babylonians built a seven-star altar to worship the stars. The seven-star altar is divided into seven layers, and each layer has a star god. There are seven gods from top to bottom: sun, moon, fire, water, gold, wood and earth. The seven gods are in charge of one day of the week, so they sacrifice one god every day and name it after another.